Formaldehyde-free protein-containing binder compositions

ABSTRACT

One-part binder compositions are described that may include a protein and a crosslinking combination. The crosslinking combination may include at least a first crosslinking compound and a second crosslinking compound. The first and second crosslinking compounds are individually crosslinkable with each other and with the protein. Examples of the protein include soy protein. Fiber products and methods of making the fiber products are also described. The fiber products may include organic fibers, inorganic fibers, or both, in a cured thermoset binder based on solutions of the one-part binder compositions.

BACKGROUND OF THE INVENTION

Thermoset binders for composite fiber products such as fiberglassinsulation are moving away from traditional formaldehyde-basedcompositions. Formaldehyde is considered a probable human carcinogen, aswell as an irritant and allergen, and its use is increasingly restrictedin building products, textiles, upholstery, and other materials. Inresponse, binder compositions have been developed that do not useformaldehyde or decompose to generate formaldehyde.

One type of these formaldehyde-free binder compositions rely onesterification reactions between carboxylic acid groups in polycarboxypolymers and hydroxyl groups in alcohols. Water is the main byproduct ofthese covalently crosslinked esters, which makes these binders moreenvironmentally benign, as compared to traditional formaldehyde-basedbinders. However, these formaldehyde-free binder compositions also makeextensive use of non-renewable, petroleum-based ingredients. Thus, thereis a need for formaldehyde-free binder compositions that rely less onpetroleum-based ingredients.

As an abundant and renewable material, protein has great potential to bean alternative to petroleum-based binders. Proteins are already usedextensively as a component of adhesives for various substrates. However,many types of protein-containing adhesives have poor gluing strength andwater resistance. Thus, there is a need to improve the bonding strengthand water resistance of protein-containing binder compositions to levelsthat are similar to or better than those of conventional,petroleum-based binder compositions. These and other issues areaddressed in the present Application.

BRIEF SUMMARY OF THE INVENTION

One-part binder compositions are described that may include one or moreproteins that actively crosslink with other binder constituents toprovide a rigid thermoset binder. The binder compositions areformaldehyde-free, and incorporate renewable materials like proteinsfrom animal and vegetable sources (e.g., soy flour) that reduce or eveneliminate the need for petroleum-based binder ingredients. Thecomponents of the binder compositions may be selected to increase thepot life and reusability of pre-cured binder solutions withoutcompromising on the quality of the cured binder product.

The binder compositions may include one-part compositions that can becured without the addition of another compound. However, additionalcompounds such as a cure catalyst may optionally be added to acceleratethe rate of curing or some other function. In addition, changes intemperature and/or other external conditions may be effected to cure thebinder composition and produce a final product containing the curedbinder.

Exemplary binder compositions may include at least three components thatare all capable of forming covalent bonds with each other. Thesecomponents may include at least one protein and a crosslinkingcombination of two or more crosslinking compounds. The crosslinkingcompounds may include a first crosslinking compound (e.g., a polymercompound) and a second crosslinking compound (e.g., a crosslinkingagent) that are individually crosslinkable with each other and with theprotein. For example the binder composition may include a protein,polymer compound and crosslinking agent that all have functional groupscapable of forming covalent bonds with each other. The protein mayinclude hydroxyl and carboxyl groups that can form covalent bonds withcomplementary carboxyl and hydroxyl groups on the polymer compound andcrosslinking agent. Similarly, the polymer compound and crosslinkingagent are selected with complementary functional groups to form covalentbonds with each other (e.g., a polycarboxy polymer and hydroxyl-groupcontaining crosslinking agent such as an amino alcohol). When all threegroups are capable of forming covalent bonds with each other, thecovalent bonding density in the cured binder may be higher than inbinders where only two components form such bonds.

The increased covalent bond density in a binder system with three ormore covalently bonding compounds may also allow the selection of morestable compounds for a one-part binder composition. For example,proteins, polymer compounds, and/or crosslinking agents may be selectedthat undergo covalent crosslinking reactions at a slower rate (e.g., areaction rate that is about zero) under ambient conditions (e.g., roomtemperature), thereby extending the pot life (a.k.a. shelf life) of theone-part binder composition. The stability of the individual compoundsmay be selected to give the one-part binder composition a pot life about1 month or more.

Embodiments of the invention include one-part thermoset bindercompositions that may include a protein and a crosslinking combinationof two or more crosslinking compounds. The crosslinking combination mayinclude a first crosslinking compound and a second crosslinkingcompound, where the first and second crosslinking compounds areindividually crosslinkable with each other and with the protein. Onespecific, non-limiting example of the present binder compositionsincludes a polymer compound; a crosslinking agent crosslinkable with thepolymer compound; and a protein that is crosslinkable with both thepolymer compound and the crosslinking agent. The protein may include soyprotein which may, for example, be sourced from soy flour.

Embodiments of the invention may further include fiber products. Thefiber products may include inorganic or organic fibers (or both) and acured thermoset binder prepared from a one-part binder solution. Thebinder solution may include a protein and a crosslinking combination oftwo or more crosslinking compounds, where the protein and crosslinkingcompounds are all crosslinkable with each other.

Embodiments of the invention may still further include methods of makinga fiber product. The methods may include the steps of providing fibersthat may be organic fibers or inorganic fibers, and applying a one-partbinder solution to the fibers. The one-part binder solution may includea protein and a crosslinking combination of two or more crosslinkingcompounds, where the protein and crosslinking compounds are allcrosslinkable with each other. The methods may further include reusingan unused portion of the one-part binder solution in a subsequentapplication of the one-part binder solution to the same fibers or adifferent group of fibers.

Additional embodiments and features are set forth in part in thedescription that follows, and in part will become apparent to thoseskilled in the art upon examination of the specification or may belearned by the practice of the invention. The features and advantages ofthe invention may be realized and attained by means of theinstrumentalities, combinations, and methods described in thespecification.

BRIEF DESCRIPTION OF THE DRAWINGS

A further understanding of the nature and advantages of the presentinvention may be realized by reference to the remaining portions of thespecification and the drawings wherein like reference numerals are usedthroughout the several drawings to refer to similar components. In someinstances, a sublabel is associated with a reference numeral and followsa hyphen to denote one of multiple similar components. When reference ismade to a reference numeral without specification to an existingsublabel, it is intended to refer to all such multiple similarcomponents.

FIG. 1 is a graph of dogbone composite tensile tests for a selection ofbinder compositions described in the Examples below.

DETAILED DESCRIPTION OF THE INVENTION

One-part binder compositions are described that include renewablematerials such as proteins in combination with two or more other bindercomponents. Examples include one-part binder compositions made from atleast one protein and a crosslinking combination of two or morecrosslinking compounds, where the protein and crosslinking compounds areall crosslinkable with each other. The term “crosslinkable” refers tothe ability of two compounds to form covalent bonds with each other,although other type of bonds may also be formed between the compounds.The one-part binder composition may optionally include additionalcomponents such as cure catalysts.

Binder solutions made from the present binder compositions may beapplied to a substrate such as inorganic and/or organic fibers and curedto make a composite of the thermoset binder and substrate such as abuilding material (e.g., fiberglass insulation). These materials do notoff-gas formaldehyde during their production and use, or decompose tocontaminate factories, buildings, homes, and other areas withformaldehyde. Furthermore, the binder compositions may at leastpartially substitute renewable compounds (e.g., proteins) fornon-renewable compounds such as petroleum-based compounds.

Exemplary Binder Compositions:

Exemplary binder compositions may include compositions containing atleast one protein and a crosslinking combination of two or morecrosslinking compounds, where the protein and crosslinking compounds areall crosslinkable with each other. The proteins used in the bindercompositions may include vegetable and/or animal proteins. Theseproteins may be readily available from a renewable source. Examples ofproteins that may be used in the binder compositions include soyprotein, wheat protein, corn protein, whey, albumin, keratin, gelatin,collagen, gluten, casein, among other kinds of proteins.

The proteins may be used in an unmodified, un-denatured state (i.e.,native proteins). Alternatively, the proteins may be modified and/ordenatured using physical, chemical, or enzymatic methods that causechanges to the primary, secondary, tertiary, and/or quaternarystructures of the proteins. These methods may include denaturing theproteins to change their secondary, tertiary and quaternary structures,and chemically or enzymatically breaking down the protein molecules intosmaller fragments. They may also include modifying the pendant moietiesof the protein, such as adding additional carboxyl and/or hydroxylgroups to the protein molecules.

One example of a protein used in the invention may be soy protein in theform of a soy flour, soy protein concentrate, soy protein isolate,and/or soy polymer, among other forms of soy protein. Soy flour may beproduced by grinding soybeans into a powder. Soy flour may retain thenatural oils and other compounds from the soybeans, or may be defattedto produce flour with higher protein content (e.g., about 50 wt %protein or more). Soy protein concentrate contains about 70 wt % soyprotein and is made by removing water soluble carbohydrates fromdefatted soy flour. Soy protein isolate is a highly refined, purifiedform of soy protein with the protein content of about 90 wt. % or more.The isolates may be made from defatted soy flour that has mostnon-protein soybean components removed (e.g., fats, carbohydrates,etc.). Soy polymers may include soy proteins that have been chemicallymodified to impart a variety of functionalities to protein molecules.

The soy protein may be denatured/modified to unfold protein molecules inthe dispersion. Upon unfolding, the functionalities of protein molecules(e.g., carboxyl, hydroxyl, and amine) are exposed and may actively reactwith other binder ingredients to form crosslinking bonds. Examples ofprotein denaturation and modification methods include, but not limitedto, heat treatment, treatment with chaotropic agents (e.g., urea,guanidinium chloride, and lithium perchlorate), acids, bases, metalsalts, alcohols, detergents, thiols, sulfites, and mixtures thereof.

The soy protein may also be modified to reduce the viscosity of soyprotein dispersion, therefore reducing the viscosity of protein-basedthermoset binder compositions. Examples of methods of reducing theviscosity of soy protein dispersion include, but not limited to,hydrolyzing protein using enzymes or alkalis, cleaving disulfide bondsin protein by thiols or sulfites. For example, the viscosity of soyprotein dispersion may be reduced by the treatment with sodiumbisulfite.

The relative amount of protein to add can vary depending on other bindercomponents used, the processing conditions, and the type of end productbeing made, among other considerations. Embodiments have theconcentration of the protein (as a percentage weight of the bindercomposition) ranging from about 5% to about 95%; about 10% to about 90%;about 25% to about 80%; about 20% to about 60%; about 20% to about 50%;about 30% to about 70%; etc.

Soy protein such as soy flour may be dispersed or dissolved in water.Other binder ingredients, such as the crosslinking compounds (e.g.,monomer and polymer compounds, crosslinking agents, etc.), are mixedwith the aqueous soy protein dispersion or solution to form the finalbinder composition that is applied to the fibrous products.

The crosslinkable combination of crosslinking compounds may includemonomeric compounds and/or polymer compounds, among other classes ofcrosslinking compounds. These crosslinking compounds may be selected tohave complementary functional groups that can react to form covalentbonds. For example, one crosslinking compound may be acarboxyl-containing polycarboxy polymer, while a second crosslinkingcompound may be crosslinking agent that includes hydroxyl groups thatreact to form covalent bonds with the carboxyl groups. Similarly, thepolymer compound may have reactive hydroxyl groups and the crosslinkingagent may have reactive carboxyl groups that react to form covalentbonds.

Examples of carboxyl-containing polymer compounds include polycarboxyhomopolymers and/or copolymers prepared from ethylenically unsaturatedcarboxylic acids including, but not limited to, acrylic acid,methacrylic acid, butenedioic acid (i.e., maleic acid and/or fumaricacid), methyl maleic acid, itaconic acid, and crotonic acid, among othercarboxylic acids. The polycarboxy polymer may also be prepared fromethylenically unsaturated acid anhydrides including, but not limited to,maleic anhydride, acrylic anhydride, methacrylic anhydride, itaconicanhydride, among other acid anhydrides. Additionally, the polycarboxypolymer of the present invention may be a copolymer of one or more ofthe aforementioned unsaturated carboxylic acids or acid anhydrides andone or more vinyl compounds including, but not limited to, styrenes,acrylates, methacrylates, acrylonitriles, methacrylonitriles, amongother compounds. More specific examples of the polycarboxy polymer mayinclude copolymers of styrene and maleic anhydride, and its derivativesincluding its reaction products with ammonia and/or amines. For example,the polycarboxy polymer may be the polyamic acid formed by the reactionbetween the copolymer of styrene and maleic anhydride and ammonia.

The polymer compound may be a solution polymer that helps make a rigidthermoplastic binder when cured. In contrast, when the polymer compoundis an emulsion polymer, the final binder compositions are usually lessrigid (i.e., more flexible) at room temperature.

Crosslinking agents may include compounds containing at least tworeactive functional groups including, but not limited to, hydroxyl,carboxyl, amine, aldehydes, isocyanate, and epoxide, among otherfunctional groups. Examples of crosslinking agents may include polyols,alkanol amines, polycarboxylic acids, polyamines, and other types ofcompounds with at least two functional groups that can undergocrosslinking of with other binder ingredients, such as proteins andpolymer compounds.

Specific examples of polyols may include glycerol, ethylene glycol,propylene glycol, diethylene glycol, and triethylene glycol, among otherpolyols. Specific examples of alkanol amines may include ethanolamine,diethanolamine, and triethanolamine, among other alkanol amines.Specific examples of polycarboxylic acids may include malonic acid,succinic acid, glutaric acid, citric acid, propane-1,2,3-tricarboxylicacid, butane-1,2,3,4-tetracarboxylic acid, among other polycarboxylicacids. Specific examples of polyamines may include ethylene diamine,hexane diamine, and triethylene diamine, among other polyamines.Specific examples of epoxies may include bisphenol-A based epoxies,aliphatic epoxies, epoxidized oils, among other epoxy compounds.

The crosslinking agent may react with both the polymer compound and theprotein. For example, when the polymer compound is a polycarboxy polymerthe crosslinking agent may be a polyol that is capable of reacting withnot only the protein (e.g., soy protein) but also the polycarboxypolymer.

As noted above, the binder compositions may include three componentsbinders made from a single protein and a two-compound crosslinkingcombination. In addition, binder compositions may include a plurality ofproteins and compounds that make up the crosslinking combination (e.g.,a plurality of polymer compounds, and/or crosslinking agents). Forexample, two or more types of one component may be combined with asingle species of each of the other components. In addition, two or moretype of two of the components may be combined with a single species of athird component. Also, two or more types of all three components may bepresent in the binder composition.

The binder compositions may also optionally include a cure catalyst.Examples of cure catalysts may include phosphorous-containing compoundssuch as phosphorous oxyacids and their salts. For example, the curecatalyst may be an alkali metal hypophosphite salt like sodiumhypophosphite (SHP). The cure catalyst may be added to expedite curingof the binder composition.

The binder compositions may also optionally include extenders. Examplesof extenders may include starch, lignin, rosin, among other extenders.

The binder compositions may also optionally contain pH adjustmentagents. For example, the present binder compositions and solution mayinclude one or more bases that maintain the pH at about 7 or more, about8 or more, about 9 or more, about 9.5 or more, about 10 or more, about10.5 or more, etc.

The protein in the binder composition may be actively crosslinkable withthe members of the crosslinking combination. The protein may be treatedto expose the reactive moieties on polypeptide chains of the proteins(e.g., hydroxyl groups, carboxyl groups, amino groups, thiol groups) forcrosslinking reactions. For example, the hydroxyl-containing amino acidmoiety on protein chains (e.g., serine, tyrosine, threonine) may reactin an esterification reaction with a carboxyl group on the polycarboxypolymer. Similarly, a carboxyl-containing amino acid moiety (e.g.,aspartic acid, glutamic acid) may react with a hydroxyl on thecrosslinking agent to actively crosslink the protein in the bindercomposition.

While not wishing to be bound by a particular theory, it is thought thatthe reactions between reactive moieties on the protein, and thecompounds of the crosslinking combination provide crosslinking betweenthese compounds to create a rigid thermoset binder when cured.

The present binder compositions may also exclude materials that havedeleterious effects on the cured binder. For example, the bindercompositions may have decreased levels of reducing sugars (or noreducing sugars at all) to reduce or eliminate Maillard browning thatresults from the reaction of these sugars at elevated temperatures. Somebinder compositions made from renewable materials can containsubstantial levels of reducing sugars and other carbohydrates thatproduce a brown or black color in the cured binder. As a result,products made with these binder compositions are difficult or impossibleto dye.

Examples of the present binder compositions include compositions wherethe concentration of reducing sugars is decreased to a point wherediscoloration effects from Maillard browning are negligible. The fullycured binders may have a white or off-white appearance that allows themto be easily dyed during or after the curing process.

Methods of Making Fiber Products:

The present binder compositions may be used in methods of making fiberproducts. The methods may include applying a solution of the bindercomposition to fibers and curing the binder composition on the fibers toform the fiber product. The binder solution may be spray coated, spincoated, curtain coated, knife coated, or dip coated onto fibers. Oncethe liquid binder composition is applied, the binder and substrate maybe heated to cure the binder composition and form a composite of curedbinder and fibers that make up the fiber product.

The binder solution may be formed to have a viscosity in range thatpermits the efficient application of the solution to the fibers. Forexample, the viscosity may be about 1 centipoises to about 1000centipoises when the binder solution is at room temperature.

If the viscosity of the liquid binder applied to the substrate is toohigh, it may slow down the application process both at the release pointfor the binder as well as the rate of mixing and coverage of the binderon the substrate. Solutions and dispersions of many types of protein,including some types of soy protein in aqueous solutions, have generallyhigh viscosities. Thus, the present protein-containing bindercompositions may include proteins with a relatively low viscosity whendissolved/dispersed in the liquid binder. These may include soy proteinsthat are modified to lower the viscosity of soy protein dispersion.

After application of the liquid binder composition on the substrate, theamalgam of liquid binder and substrate undergoes curing. In the curingprocess the protein, polymer compound, and crosslinking agent may formcovalently crosslinked bonds among each other to convert the amalgaminto a thermoset composite. When a thermal curing process is used, theamalgam may be subjected to an elevated temperature (e.g., up to 300°C.) to facilitate crosslinking in the binder. The peak curingtemperature may depend on the specific formulation of theprotein-containing binder composition, the substrate, and whether a curecatalyst is used. The cured material typically includes about 0.5 wt %to about 50 wt % thermoset binder composition (e.g., about 1 wt. % toabout 10 wt. %) with the substrate representing most of the remainingweight.

The binder composition may be a stable one-part composition that can berecycled during the application to the fibers and/or betweenapplications on fibers. Thus, an unused portion of the binder solutionthat, for example, passes through the fibers may be captured and sentback to the supply of binder solution applied to the fibers. In someembodiments, the unused portion of the binder solution may be purifiedor otherwise treated before returning to the supply.

The reuse of the binder solution may not only reduce the amount ofsolution used, it may also reduce the amount of waste materials thatmust be treated and discarded. However, recycling unused binder solutionrequires that the solution remain stable for two or more applicationcycles. In many instances, two-part binder compositions that mixseparated and highly reactive components immediately before theirapplication will cure too rapidly to be recycled. One-part bindercompositions may also be unsuitable if they don't have a sufficient potlife to remain relatively unreacted prior to use and during recycling.The present binder compositions include one-part binder compositionsthat are stable enough to be appropriate for binder solution recycling.

Fiber Products:

The present binder compositions may be added to fibers to producecomposite fiber products. The fibers may include organic fibers and/orinorganic fibers. For examples of the fibers may include polymer fibersand/or glass fibers, among other types of fibers. The fibers may bearranged as an insulation batt, woven mat, non-woven mat, or spunbondproduct, among other types of fiber substrate.

The present binder compositions may be used in fiber products to makeinsulation and fiber-reinforced composites, among other products. Theproducts may include fibers (e.g., organic and/or inorganic fibers)contained in a cured thermoset binder prepared from a one-part bindersolution of a polymer compound, crosslinking agent that is crosslinkablewith the polymer compound, and protein crosslinkable with both thepolymer compound and crosslinking agent. The fibers may include glassfibers, carbon fibers, and organic polymer fibers, among other types offibers. For example, the combination of the binder composition and glassfibers may be used to make fiberglass insulation products.Alternatively, when the fiberglass is a microglass-based substrate, thebinder may be applied and cured to form printed circuit boards, batteryseparators, filter stock, and reinforcement scrim, among other articles.

The binder compositions may be formulated to impart a particular colorto the fiber product when cured. For example, the concentration ofreducing sugars in the binder compositions may be lowered to give thefiber product a white or off-white color when cured. Alternatively, adye may be added to binder composition before, during, or after thecuring stage to impart a particular color to the final fiber product(e.g., red, pink, orange, yellow, green, blue, indigo, violet, among mayother colors).

EXPERIMENTAL

The following Examples are presented to provide specific representativeembodiments of the present invention. It should be understood, however,that the invention is not limited to the specific details as set forthin these Examples.

Example #1 Modification of Soy Flour

50 grams of defatted soy flour (Prolia 200/90, Cargill) is dispersed in200 ml of DI water at room temperature. 0.5 grams of sodium bisulfite isthen added to the soy flour dispersion. The viscosity of the soy flourdispersion drops shortly after the addition of the sodium bisulfite. Thefinal soy flour dispersion has a solids concentration of 18.9% by ovenmethod (drying at 125° C. for 2 hours).

Example #2 Modification of Soy Flour

50 grams of defatted soy flour (Prolia 200/90, Cargill) is dispersed in200 ml of DI water at room temperature. 0.5 grams of sodium bisulfite isthen added to the soy flour dispersion. After the viscosity of the soyflour dispersion is decreased to a stable region, the pH of thedispersion is adjusted to 11 using an ammonium hydroxide solution(25-30%). The final soy flour dispersion has a solids concentration of17.5% by oven method.

Example #3 Preparation of Polyamic Acid Resin (SMAc-TEA)

To a flask equipped with a reflux condenser is added 1,735 grams ofwater and 234 grams of 30% by weight aqueous solution of ammonia. Tothis solution is added 960 grams of a copolymer of styrene and maleicanhydride (SMA) having a molecular weight of approximately 2,000 and anacid number of 480. The mixture is then heated to 90° C. and maintainedat 90° C. under constant stirring until a clear solution of polyamicacid is obtained. To the obtained polyamic acid solution is added 306grams of triethanolamine. The final polyamic acid resin, hereinafterreferred to as SMAc-TEA, has a solids of 42.4% and a pH of 6.8.

Example #4 Preparation of a Binder Composition of Modified Soy Flour andSMAc-TEA

To 79.4 grams of the soy flour dispersion of Example 1 is added withstirring 23.6 grams of the polyamic acid resin of Example 3, and 22grams of water to achieve a total solids of 20% and a weight ratiobetween soy flour and SMAc-TEA of 60/40. The final binder composition isthen used for dogbone composite tensile test as described below inExample 8.

Example #5 Preparation of a Binder Composition of Modified Soy Flour andSMAc-TEA

To 85.7 grams of the soy flour dispersion of Example 2 is added withstirring 23.6 grams of polyamic acid resin of Example 3 and 15.7 gramsof water to achieve a total solids of 20% and a weight ratio between soyflour and SMAc-TEA of 60/40. The final binder composition is then usedfor dogbone composite tensile test as described below in Example 8.

Example #6 Preparation of a Binder Composition of Modified Soy Flour andSMAc-TEA

To 57.1 grams of the soy flour dispersion of Example 2 is added withstirring 35.4 grams of polyamic acid resin of Example 3 and 32.5 gramsof water to achieve a total solids of 20% and a weight ratio between soyflour and SMAc-TEA of 40/60. The final binder composition was then usedfor dogbone composite tensile test as described below in Example 8.

Example #7 Preparation of a Binder Composition of Modified Soy Flour andSMAc-TEA

To 28.6 grams of the soy flour dispersion of Example 2 is added withstirring 47.2 grams of polyamic acid resin of Example 3 and 49.2 gramsof water to achieve a total solids of 20% and a weight ratio between soyflour and SMAc-TEA of 20/80. The final binder composition is then usedfor dogbone composite tensile test, which is described below in Example8.

Example #8 Dogbone Composite Tensile Test

The four soy flour-containing binder compositions of Examples 4-7 andSMAc-TEA resin of Example 3 are evaluated via a dogbone tensile testmethod. Binder solutions are prepared from the five binder compositionsby adding 5%, by weight, of sodium hypophosphite monohydrate and 1%, byweight, of aminosilane (Silquest A-1100). The binder solutions are mixedwith glass beads to achieve a binder content of 2.4% for each compositeof binder and glass beads. The composites are then pressed in molds ofdogbone shape to form test samples. The molded samples are then driedand cured in an oven at 204° C. for 20 minutes.

Tensile tests are conducted on the dogbone composite samples before andafter humid aging. The aging process involves exposing the dogbonesamples containing the cured binder to air at a temperature of 120° F.,with 95% relative humidity for 24 hours. FIG. 1 shows the tensilestrength results for the five binder compositions described in Examples3-7 before and after humid aging. In FIG. 1, “SF” stands for “soyflour”. The data shown in FIG. 1 represent the average of nine dogbonespecimens for each sample and the error represents the standarddeviation.

The tensile tests show that the binder compositions with soy flour thatis not ammonia-modified yield a lower tensile strength, as compared tothe binder composition without soy flour (e.g., SMAc-TEA). Significantincrease in tensile strength was observed when soy flour wasammonia-modified. As shown in FIG. 1, all binder compositions containingammonia-modified soy flour show higher tensile strength than the bindercomposition without soy flour (e.g., SMAc-TEA). The humid-agingretention of tensile strength of all the binder compositions containingammonia-modified soy flour is very high (>95%), indicating the highmoisture resistance of the protein-based binder compositions of thepresent invention.

Having described several embodiments, it will be recognized by those ofskill in the art that various modifications, alternative constructions,and equivalents may be used without departing from the spirit of theinvention. Additionally, a number of well-known processes and elementshave not been described in order to avoid unnecessarily obscuring thepresent invention. Accordingly, the above description should not betaken as limiting the scope of the invention.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimits of that range is also specifically disclosed. Each smaller rangebetween any stated value or intervening value in a stated range and anyother stated or intervening value in that stated range is encompassed.The upper and lower limits of these smaller ranges may independently beincluded or excluded in the range, and each range where either, neitheror both limits are included in the smaller ranges is also encompassedwithin the invention, subject to any specifically excluded limit in thestated range. Where the stated range includes one or both of the limits,ranges excluding either or both of those included limits are alsoincluded.

As used herein and in the appended claims, the singular forms “a”, “an”,and “the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “a process” includes aplurality of such processes and reference to “the protein” includesreference to one or more proteins and equivalents thereof known to thoseskilled in the art, and so forth.

Also, the words “comprise,” “comprising,” “include,” “including,” and“includes” when used in this specification and in the following claimsare intended to specify the presence of stated features, integers,components, or steps, but they do not preclude the presence or additionof one or more other features, integers, components, steps, acts, orgroups.

What is claimed is:
 1. A one-part binder composition comprising anaqueous mixture of: a protein; and an aqueous solution comprising atleast a first crosslinking compound comprising a solution polymercompound of styrene and maleic anhydride and a second crosslinkingcompound comprising a crosslinking agent of a polyol, an alkanol amine,or a polyamine, wherein the first and second crosslinking compounds areindividually crosslinkable with each other and with the protein, andwherein the aqueous solution does not include an emulsion of the firstcrosslinking compound or the second crosslinking compound.
 2. Theone-part binder composition of claim 1, wherein the one-part bindercomposition is cured without an addition of another compound.
 3. Theone-part binder composition of claim 1, wherein the protein comprisessoy protein.
 4. The one-part binder composition of claim 3, wherein thesoy protein comprises soy flour, soy protein concentrate, soy proteinisolate, or soy polymer.
 5. The one-part binder composition of claim 1,wherein the protein comprises soy flour.
 6. The one-part bindercomposition of claim 1, wherein the protein comprises about 5% to about95%, by wt., of the binder composition.
 7. The one-part bindercomposition of claim 1, wherein the protein comprises about 25% to about80%, by wt., of the binder composition.
 8. The one-part bindercomposition of claim 1, wherein the crosslinking agent comprises anamino alcohol.
 9. The one-pan binder composition of claim 8, wherein theamino alcohol comprises triethanolamine.
 10. The one-part bindercomposition of claim 1, wherein the binder composition further comprisesa cure catalyst.
 11. The one-part binder composition of claim 1, whereinthe binder composition has a pH greater than about
 7. 12. The one-partbinder composition of claim 1, wherein the binder composition has a pHof about 10.5 or more.
 13. The one-part binder composition of claim 1,wherein the binder composition has a decreased concentration of areducing sugar.
 14. The one-part binder composition of claim 1, whereinthe aqueous mixture comprises a dispersion of the protein in the aqueoussolution of the first crosslinking compound and the second crosslinkingcompound.